Various apparatus are available that receive strips of cut material and then manipulate the material strips such as by either or both rotating or pivoting the strips relative to their initial direction of movement and then placing such material strips on or near a continuously moving surface. In placing the strips of material relative to the moving surface, such apparatus generally begin the placement by initially contacting the leading edge of the strip with the moving surface and then progressively laying or rolling the strip upon the surface with the trailing edge of the strip being the last to be laid upon the moving surface.
A problem that exits with these apparatus is that rotation of the transferring element, upon which the strip is carried, can cause the transferring element to bite or dig into the moving surface, thereby undesirably cutting or otherwise damaging the moving surface. For example, as the transferring element releases the leading edge of the material strip and then begins to pivot or rotate upwardly away from the moving surface, the trailing edge of the transferring element pivots or rotates against and into the moving surface. This can either or both damage the moving surface and disrupt the proper positioning or registration of the strip with the moving surface, and is particularly undesirable when the moving surface is a woven or nonwoven material.
This problem is particularly acute when the strip being laid upon the moving surface is of a generally elongate or rectangular shape having its longest axis parallel to the direction of movement of the moving surface.
Another frequently occurring problem in such processing relates to the proper releasing of the strip of material from the transferring element to the moving surface. Generally, such strips of material are held on their respective transferring elements via a vacuum effect created or transmitted through perforations or holes in the outer surface of the transferring element. Unfortunately, these apparatus may not extinguish or otherwise release the vacuum against the strip of material as the strip of material is progressively transferred leading edge to trailing edge on the moving surface. For example, if the vacuum is not progressively extinguished as the strip is progressively laid from the transferring element onto the surface, portions of the strip element can continue to be held by vacuum against the transferring element resulting in an undesirable pleat or fold in the strip material, skewed alignment of the strip material with the moving surface, and the like.
In view of these and other perceived shortcomings in prior existing apparatus and processing relating to the receiving and rotating strips of material and then placing the rotated strips relative to a continuously moving surface, a new applicator apparatus and application process have been developed and are the subject of Pohjola, U.S. Pat. No. 5,104,116, issued Apr. 14, 1992, and Pohjola, U.S. Pat. No. 5,224,405, issued Jul. 06, 1993, the disclosures of each of which is incorporated herein by reference in its entirety. In accordance therewith, a strip of material is received and rotated toward a continuously moving surface, and then orientated so that the surface thereof is placed generally flat with the continuously moving surface via one or more puck rotating means. In accordance with certain preferred embodiments thereof, the apparatus additionally includes a surface-leveling means for positioning the puck surface in an appropriate spaced-apart relationship with the moving surface. To that end, these patents disclose puck assemblies which in addition to rotating, pivot such that the puck surface is placed flat against or with the moving surface, as desired, and such as may employ open cams.
While such apparatus and associated processing have represented a significant advancement in the art and have generally been successful in overcoming, reducing or minimizing at least some of the problems or shortcomings of earlier apparatus and processing, such apparatus and processing may at least at times be subject to certain limitations. For example, the employment of features such as puck members which both pivot and rotate such as to receive, rotate and deposit such material strips may result in the undesirable introduction of oscillating or reciprocating motion into the apparatus and processing.
As will be appreciated, such motion may interfere with desired operation. In particular, such oscillating or reciprocating motion may complicate or prevent either or both the proper positioning and placement of the strip of material on an associated moving surface. Also, the requirement to oscillate or reciprocate mass introduces inertia and can act as a speed limiter because force increases with speed. Reciprocating or oscillating motions can limit process speed because inertial forces in the mechanism can exceed the capability of engineering materials and methods. In addition, reciprocating or oscillating mechanisms tend to require frequent and costly maintenance due to wear caused by high inertial forces.
Thus, there remains a need and a demand for further improvements with respect to apparatus and processing for receiving and rotating strips of material and then placing the rotated strips in surface contact with a continuously moving surface.